Sweetening and cleaning system for lapping machines

ABSTRACT

A sweetening and cleaning system that is used with one or more lapping machines to sweeten a lapping compound in a sweetening mode, and to clean parts of the system itself and parts of the one or more lapping machines with a cleaning compound in a cleaning mode. The system includes a virgin receptacle for holding the lapping compound, a cleaning receptacle for holding the cleaning compound, a waste receptacle for holding waste, and at least one pump.

TECHNICAL FIELD

This invention relates to lapping machines and more particularly to sweetening and cleaning systems for lapping machines.

BACKGROUND OF THE INVENTION

Lapping machines are conventionally used to rub two surfaces together with an abrasive lapping compound between them. In the automotive industry, gears are often lapped together to, among other things, produce smooth surfaces and tight tolerances between the gears. Over time the lapping compound can become contaminated and less effective, and build-up can accumulate in piping components.

One example of a slurry managing system is U.S. Pat. No. 5,799,643 to Miyata et al. The system is used with wire saws for cutting wafers. A mixing tank mixes base oil from a dispersing tank with abrasive grains from a hopper to produce a mixed slurry. The mixed slurry is held in a reserve tank before it is pumped through the wire saws and then to a slurry waste tank. From the waste tank, the waste is decanted and filtered, and the remaining slurry is directed back to the mixing tank. Simultaneously, fresh slurry is provided to the wire saws, thus replacing the waste. This slurry managing system, however, does not have both a sweetening and cleaning mode.

SUMMARY OF THE INVENTION

One aspect of the invention includes a sweetening and cleaning system that can be used with one or more lapping machines to sweeten a lapping compound in a sweetening mode, and to clean parts of the system itself and parts of the one or more lapping machines with a cleaning compound in a cleaning mode. The system may comprise a virgin receptacle to hold the lapping compound, a cleaning receptacle to hold the cleaning compound, a waste receptacle to hold waste, and at least one pump to pump the compounds and the waste throughout the system.

Another aspect of the invention provides a method of sweetening and cleaning one or more lapping machines which may comprise a virgin receptacle for holding a lapping compound, a cleaning receptacle for holding a cleaning compound, and a waste receptacle for holding waste. The method comprises at least a sweetening mode and a cleaning mode. The sweetening mode may include removing waste out of the one or more lapping machines and putting it into the waste receptacle, and adding the lapping compound to the one or more lapping machines. The cleaning mode may include purging the one or more lapping machines of waste, and priming the one or more lapping machines with the lapping compound.

Yet another aspect of the invention includes a sweetening and cleaning system that can be used with one or more lapping machines that may comprise a virgin receptacle for holding a lapping compound, a cleaning receptacle for holding a cleaning compound, a waste receptacle for holding waste, a first pump, a second pump, and a three-way valve.

BRIEF DESCRIPTION OF THE DRAWINGS

Preferred exemplary embodiments of the invention will hereinafter be described in conjunction with the appended Figure which is a schematic representing a sweetening and cleaning system of this invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Referring now to the Figure, it shows an embodiment of a sweetening and cleaning method and system 10 that can be used with one or more lapping machines 12, such as a group of six lapping machines (not shown). The system may be retrofitted on a group of lapping machines, or installed as part of the original equipment of the machines. In any case, the sweetening and cleaning system 10 sweetens a lapping compound that is used in the lapping machines 12 by routinely improving the lapping compound during a sweetening mode, and the system 10 cleans parts of itself and parts of the lapping machines 12 by using a cleaning compound during a cleaning mode. The sweetening and cleaning system 10 may include a virgin receptacle 14 that holds the lapping compound, a cleaning receptacle 16 that holds the cleaning compound, and a waste receptacle 18 that holds waste. Various piping components may also be included that control fluid-flow between the receptacles and the lapping machines 12, and a programmable logic controller (PLC) 20 may be included to serve as the control center for the system.

The lapping machines 12 are commonly used to lap surfaces such as gears for an automobile. As mentioned, the sweetening and cleaning system 10 can be retrofitted on one or more lapping machines 12. If so, the system's hardware components are installed to the existing lapping machines 12, and the system's software is programmed to communicate with software on the lapping machines 12, and vice versa. Each lapping machine 12 may include a machine cell 22 where the actual lapping of the parts takes place, and a machine reservoir 24 to collect and hold lapping compound as it is being used in the machine. Some lapping machines have a high level sensor 26 and a low level sensor 28 to sense when the compound in the machine reservoir 24 is at a respective high and low level. In addition to communicating with these level sensors, the sweetening and cleaning system 10 may further include a first level sensor 30 and a second level sensor 32 that are equipped in the machine reservoir 24. The first level sensor 30 is one that can be manually adjusted, such as the known vertical stem type. This way the machine operator can calibrate, or set, the sensor to determine the amount of waste that is pumped out of the machine reservoir 24 during the sweetening mode as will be described below. The second sensor 32 is set to a desired level to determine the amount of lapping compound that is pumped into the machine reservoir 24 also during the sweetening mode. Lastly, a machine pump 34 may be included with each lapping machine 12 to circulate compound through the machine.

In other embodiments, the PLC 20 could be programmed for timed events. For example, in the sweetening mode, the system pumps could be energized for a predetermined amount of time in order to pump waste out of the machine reservoir 24, and then to pump lapping compound into the machine reservoir. Here, the first and second level sensors 30 and 32 may still be provided, but are only in use when the compound or waste level reaches them and the particular fluid level in the machine reservoir needs to be corrected. In other words, the timed events may result in a fluid level that is either below the first level sensor 30 or above the second level sensor 32. This can occur because of a circumstance known as drift, whereby one or more pumps produces an inexact (less or more) amount of fluid into or out of the machine reservoir 24. In one example, during a timed event in the sweetening mode, lapping compound may reach the second level sensor 32 before the timed event has expired. In this case, the PLC 20 would cut-short the timed even such that the fluid level in the machine reservoir 24 does not exceed the second level sensor 32.

The virgin receptacle 14 holds and stores the virgin, or pure, lapping compound for the sweetening and cleaning system 10. Suitable receptacles will be known to those skilled in the art. In this embodiment, the virgin receptacle 14 is a single 275 gallon receptacle, but more than one (larger or smaller) can be used. For example, two virgin receptacles can be stacked one on top of the other with an automatic control valve between the two that can be set to open by the PLC 20 when a level sensor in one indicates a low level. The lapping compound itself will depend on, among other things, the particular lapping application. One lapping compound that is suitable for automotive gears is composed of silicon carbide crystals, mineral oil, and other additives, and is supplied by Foretech Products, Inc. in Whitmore Lake, Mich. A low level sensor 36 may be provided in the virgin receptacle 14 to sense when the lapping compound is at a predetermined low level. The low level sensor 36 is set so that when it is triggered, enough lapping compound remains in the virgin receptacle 14 to complete the sweetening mode in one lapping machine 12. Similarly, an emergency low level sensor 38 may be provided in the virgin receptacle 14 and set below the low level sensor 36 to trigger when the receptacle needs to be refilled or replaced with lapping compound. Both of these level sensors can be of the known doppler type, tuning fork type, or the like. Furthermore, a quick-connect fitting (not shown) may be provided on the virgin receptacle 14 to connect and disconnect the receptacle with the piping components.

The cleaning receptacle 16 holds and stores the cleaning compound for the sweetening and cleaning system 10. Like the virgin receptacle, the cleaning receptacle 16 is a single 275 gallon receptacle and there can be more than one that is larger or smaller. The cleaning compound itself is a solution that removes build-up in the piping components and the lapping machines 12 from the particular lapping operation. One suitable cleaning compound is mineral seal oil. The cleaning receptacle 16 may have a low level sensor 40 and a high level sensor 42. The low level sensor 40 is set to trigger when the cleaning compound in the cleaning receptacle 16 is low and needs to be refilled or replaced, and conversely the high level sensor 42 is set to trigger when the cleaning compound is at a high level. Again, these sensors can be of the known doppler type, tuning fork type, or the like. The cleaning receptacle 16 may also have a quick-connect fitting (not shown) to connect and disconnect the receptacle with the piping components.

The waste receptacle 18 holds and stores waste for the sweetening and cleaning system 10. It too is a single 275 gallon receptacle and there can be more than one that is larger or smaller. The waste itself is a mixture of used lapping compound which may contain metallic fines removed during the lapping process, dulled silicon carbide crystals, tramp oils including machine lubrications, and the like, coming from the lapping machines 12; essentially the waste comprises lapping compound that is now less effective due to the lapping process. A high level sensor 44 and an emergency high level sensor 46 may be provided in the waste receptacle 18. The high level sensor 44 is set to trigger when the waste in the receptacle reaches a high level while still having enough volume to complete a sweetening event in one lapping machine 12. And the emergency high level sensor 46 is set to trigger when the waste reaches a predetermined higher level indicating that the waste receptacle 18 needs to be emptied. These sensors can be of the known doppler type, tuning fork type, or the like. A quick-connect fitting (not shown) may also be provided on the waste receptacle 18 to connect and disconnect the receptacle with the piping components.

As mentioned, the sweetening and cleaning system 10 may include various piping components including a first pump 48 that pumps the lapping compound from the virgin receptacle 14 and also pumps the cleaning compound from the cleaning receptacle 16; and a second pump 50 at each lapping machine 12 that pumps waste from the respective lapping machine directly into the waste receptacle 18. In this embodiment, both pumps are of the positive displacement type, specifically a peristaltic pump. But those skilled in the art will appreciate that other types of pumps with different flow rates can be used depending on the particular lapping operation. Examples of suitable peristaltic pumps include those supplied by Watson-Marlow Bredel (www.watson-marlow.com) like the SPX 40 style pump for the first pump 48 and the SPX 25 style pump for the second pump 50. The first pump 48 is set to produce a laminar flow when activated in the sweetening mode, and a turbulent flow when activated in the cleaning mode. And the second pump 50 is set to produce a laminar flow when activated. Of course, the exact flow rates can differ from application-to-application, and may depend on, among other things, the pumps and pipes used. Likewise, sustaining laminar and turbulent flow in a particular application may depend on, among other things, pipe diameter and pipe routing. Furthermore, running the pumps at constant flow rates provides constant displacement rates which simplifies some system calculations including the length of time that the pumps should be energized to empty or fill the machine reservoir 24 during some embodiments of the sweetening and cleaning modes.

The first pump 48 is a single pump located near the receptacles and is piped through other piping components to the virgin receptacle 14, the cleaning receptacle 16, and the lapping machines 12, and then eventually to the waste receptacle 18. In particular, the virgin and cleaning receptacles are piped to the pump's inlet, and the pump's outlet is piped to the lapping machines 12. In other embodiments, the first pump 48 could be a pair of pumps with one directly connected to the virgin receptacle 14 and the other directly connected to the cleaning receptacle 16, and then both leading to the lapping machines 12. The second pump 50, on the other hand, is located near each lapping machine 12 and piped to the waste receptacle 18, and the lapping machine 12, and could be piped to the cleaning receptacle 16. The lapping machine 12 is piped to the second pump's inlet, and the pump's outlet can be piped to both the cleaning and waste receptacles 16 and 18.

Other piping components may include various valves and filters installed in the piping of the sweetening and cleaning system 10. As shown, a three-way valve 52 is installed between the virgin receptacle 14 and the cleaning receptacle 16, and the first pump 48. One example of a suitable three-way valve is an automatic pneumatic valve with a first inlet port, a second inlet port, and an outlet port (none specifically shown) and include those supplied by Co-ax Valves Inc., Penndel, Pa. (www.coaxvalves.com); another example of a suitable three-way valve is of the rubber-lined pinch type. The three-way valve 52 permits or prevents fluid-flow between the virgin and cleaning receptacles and the first pump by being deactuated, or deenergized, open from the first inlet port to the outlet port allowing fluid-flow between the virgin receptacle 14 and the first pump 48, and being actuated, or energized, open from the second inlet port to the outlet port allowing fluid-flow between the cleaning receptacle 16 and the first pump 48. That being so, the three-way valve 52 is located downstream the virgin receptacle 14 having the first inlet port piped to the virgin receptacle, downstream the cleaning receptacle 16 having the second inlet port piped to the cleaning receptacle, and upstream the first pump 48 having the outlet port piped to the first pump.

A first two-way valve 54 is installed downstream the lapping machines 12, particularly downstream the second pump 50, and upstream the cleaning receptacle 16 to permit or prevent fluid-flow therebetween. Preferably, the first two-way valve 54 is installed close to the cleaning receptacle 16 in order to inhibit fluid from settling and drying therebetween. One example of a suitable two-way valve is an automatic pneumatic valve having an inlet port piped to the second pump 50 and an outlet port piped to the cleaning receptacle 16; another example of a suitable two-way valve is of the rubber-lined pinch type. The first two-way valve 54 is deactuated, or deenergized, closed to prevent fluid-flow, and actuated, or energized, open to allow fluid-flow. A second two-way valve 56 is installed downstream the lapping machines 12, particularly downstream the second pump 50, and upstream the waste receptacle 18 to permit or prevent fluid-flow therebetween. Preferably, the second two-way valve 56 is installed close to the waste receptacle 18 in order to inhibit fluid from settling and drying therebetween. An inlet port is piped to the second pump 50 and an outlet port is piped to the waste receptacle 18. The second two-way valve 56 is deactuated, or deenergized, closed to prevent fluid-flow, and actuated, or energized, open to allow fluid-flow.

A third two-way valve 58 is installed downstream the first pump 48 and upstream each lapping machine 12 to permit or prevent fluid-flow therebetween. An inlet port is piped to the first pump 48 and an outlet port is piped to the lapping machine 12. The third two-way valve 58 is deactuated, or deenergized, closed to prevent fluid-flow, and actuated, or energized, open to allow fluid-flow. Furthermore, a fourth two-way valve 60 is installed downstream the first pump 48 and upstream the cleaning receptacle 16 to permit or prevent fluid-flow therebetween. An inlet port is piped to the first pump 48 and an outlet port is piped to the cleaning receptacle 16. The fourth two-way valve is deactuated, or deenergized, closed to prevent fluid-flow, and actuated, or energized, open to allow fluid-flow. All of the above two-way valves can be of the automatic pneumatic type, the rubber-lined pinch type, or the like, and can be supplied by the above Co-ax Valves Inc.

A first filter 62 may be installed downstream the lapping machines 12, particularly downstream the second pump 50, and upstream the cleaning receptacle 16 to remove impurities in the cleaning compound during the cleaning mode. Likewise, a second filter 64 may be installed downstream the machine reservoir 24 of each lapping machine 12 and upstream the machine cell 22, particularly downstream the machine pump 34 to remove impurities in compound traveling therethrough. One example of suitable filters for the first and second filters can be of the liquid bag type like those supplied by Filtration Group Inc., Joliet, Ill. (www.filtrationgroup.com).

Still other piping components may include numerous ball valves installed in the sweetening and cleaning system 10. The ball valves manually permit and prevent fluid-flow by turning a handle. All the ball valves are normally open, and can be closed to isolate a particular section of the system or a particular component in order to service that section or component. One example of suitable ball valves are of the known manual full port type that open and close to respectively permit and prevent fluid-flow. As shown, a ball valve 66 is installed in the piping exiting the virgin receptacle 14, and a ball valve 68 is installed in the piping exiting the cleaning receptacle 16. Another ball valve 70 is installed before the first pump 48, and a ball valve 72 is installed after the first pump 48. A ball valve 74 is installed downstream the first pump 48, and a ball valve 76 is installed downstream the third two-way valve 58. A ball valve 78 is installed in the piping past the machine reservoir 24, a ball valve 80 is installed before the second pump 50, and a ball valve 82 is installed after the second pump 50. Furthermore, three ball valves are installed downstream the second pump 50: a ball valve 84 is installed in the piping past the second pump 50, a ball valve 86 is installed in the piping upstream the second two-way valve 56, and a ball valve 88 is installed in the piping upstream the first two-way valve 54.

Moreover, the sweetening and cleaning system 10 may include a pair of pressure relief valves to protect the first and second pumps 48 and 50. One example of suitable relief valves can be of the known spring-loaded type. To protect the pumps, a relief valve 90 is installed in the piping immediately after the first pump 48 to provide a first relief path 92 leading back to, or near, the first pump's entrance; and a relief valve 94 is installed immediately after the second pump 50 to provide a second relief path 96 leading back to, or near, the second pump's entrance. Each of the relief valves are set to open at a predetermined pressure such as 75 p.s.i., and are fitted with a sensor (not shown), such as a proximity sensor, to sense when the particular relief valve is opened. For example, if the third two-way valve 58 fails to open during one of the modes, pressure can build-up in the piping over 75 p.s.i. thus triggering the relief valve 90 located adjacent the first pump 48. This way the pressure in the piping is kept under about 75 p.s.i. The sensor sends an electrical signal to the PLC 20 to inform the machine operator of a possible failure or malfunction.

A compound analog vacuum gauge 98 and a vacuum switch 100 may be installed immediately before the respective first pump 48, and a compound analog vacuum gauge 102 and a vacuum switch 104 may be installed immediately before the second pump 50. An additional pressure gauge 106 may be installed immediately after the first pump 48, and a pressure gauge 108 may be installed immediately after the second pump 50. All of the gauges and switches can be fitted with a diaphragm isolator to prevent fluids from contacting the components. The vacuum gauges measure the vacuum at their respective locations and send that reading to the PLC 20, and the vacuum switches trip (close the switch) and can be calibrated to about 15 in Hg or more or less depending on the particular application. Furthermore, a pulsation dampener 110 may be installed after the first pump 48, and a pulsation dampener 112 may be installed after the second pump 50. The pulsation dampeners reduce hydraulic shock in the sweetening and cleaning system 10 that can come from those pumps. A single pressure transducer 114 may be installed after the first pump 48 to sense a fluid pressure thereat and produce an associated electrical signal to the PLC 20. In some instances, fluid in a particular valve may harden or otherwise clog a valve. This condition would be sensed by the pressure transducer 114 because of an associated build-up of pressure. When this happens, the PLC 20 can be programmed to pulse the particular valve open and close, while increasing the pressure thereat by energizing a pump. This will usually loosen up the clogged valve. Suitable pressure transducers can be supplied by Ashcroft.

The piping itself is designed to reduce hydraulic shock in the sweetening and cleaning system 10. For example, all of the pipes in the system have a uniform diameter such as 1.5 inches, and the pipes change directions at about 45° laterals instead of T-connections. In some embodiments, the pipes change directions in a sweeping radius that is a multiple of six times their diameter. Pipes 116 supply the lapping compound and the cleaning compound to the lapping machine 12, and pipes 118 discharge waste and the cleaning compound to the respective waste receptacle 18 and cleaning receptacle 16. A rubber hose (not shown) may be looped between the pipes 116 close to the first pump 48. The looped hose can also reduce hydraulic shock. And all of the pipes in the sweetening and cleaning system 10 can be provided with quick-connect fittings (not shown) to connect and disconnect the pipes to other piping components, such as those supplied by Victaulic, Easton, Pa. (www.victaulic.com).

As mentioned, the PLC 20 serves as the control center for the sweetening and cleaning system 10. The PLC 20 communicates with the sweetening and lapping system by reading inputs from the system including, for example, the various level sensors in the receptacles and the machine reservoir, the pressure transducer 114, and the like. Also, the PLC 20 is programmed to send outputs to control the various piping components including, for example, energizing and deenergizing the first pump 48 and the second pump 50, and energizing and deenergizing the three-way valve 52 and the two-way valves 54, 56, 58, and 60. Moreover, the PLC 20 communicates with the lapping machines 12 by, for example, reading inputs from the high and low level sensors 26 and 28. A human-machine-innerface (HMI) 120 may be provided with the PLC 20 to interact with the machine operator by allowing everyday controls including manually switching between the modes, giving the status of the sweetening and cleaning system 10, reporting alarms, and the like. As shown, the HMI 120 is located near the receptacles or at the lapping machines 12. Various controls panels (not shown) may also be provided in the sweetening and cleaning system 10 to house various electrical components of the PLC 20.

A first skid 122 and a second skid 124 may be provided in the sweetening and cleaning system 10 to carry and transport the components of the system. In this embodiment, the first skid 122 is constructed of steel to carry the virgin receptacle 14, the cleaning receptacle 16, the waste receptacle 18, the PLC 20, and the first pump 48. Likewise, the second skid 124 is constructed of steel to carry the second pump 50 and the other various piping components adjacent the second pump including the pressure gauge 108, pulsation dampener 112, and others. The second skid 124 can be equipped with wheels (not shown) on its bottom, and the various piping components can be fitted with rubber, or otherwise be flexible, so that the second skid can be moved. The first skid 122 is located farther away from the lapping machines 12 than the second skid 124.

Once the sweetening and cleaning system 10 is installed and activated, the system routinely improves the lapping compound used in the lapping machines 12, and routinely cleans itself and parts of the lapping machines 12. To do this, the PLC 20 is programmed to control the sweetening and cleaning modes. For example, the PLC 20 automatically initiates the sweetening mode after, among other possible events, a certain number of parts have been lapped in a particular lapping machine 12. For instance, after fifty parts are lapped, the lapping machine 12 temporarily stops lapping parts while the sweetening mode is run on that machine. The PLC 20 also automatically initiates the cleaning mode after, among other possible events, a certain amount of time has lapsed. For instance, after fourteen or thirty days, the particular lapping machine 12 temporarily stops lapping parts while the cleaning mode is run on that machine. The PLC 20 issues a command to clean each lapping machine 12. The operator at each machine can then either accept or reject that command. If accepted, that lapping machine ceases lapping parts while the cleaning mode is performed; and if rejected, the machine continues lapping parts. In this sense, the sweetening and cleaning system 10 is automatic—both the sweetening and cleaning modes are initiated after certain events. Still, the sweetening and cleaning system 10 can be manually operated. That is, the sweetening and cleaning modes can be initiated by the machine operator at anytime. For example, the machine operator can run the cleaning mode before the predetermined days through commands on the PLC 20 .

As explained, the sweetening and cleaning modes are run on a single lapping machine 12 at a time in a sequential order, that is, beginning with the lapping machine located physically closer to the first skid 122. This way the particular fluid is already stacked, or loaded in the pipes, for the next lapping machine which can save pumping work as compared to starting at the lapping machine farther away without stacked fluid. If two lapping machines 12 of the group are triggered for the sweetening mode at similar times, the one that triggers first in time will be sweetened first while the one that triggers second in time will be sweetened second. In other embodiments with piping, the sweetening or cleaning mode could be run on more than one lapping machine 12 simultaneously.

When the sweetening and cleaning system 10 is first installed on one or more lapping machines 12, the system and the machines have to be initially prepared, or primed, before the system is activated. Priming essentially involves filling the system with the lapping compound. This procedure can also constitute one part of the cleaning mode as will be described below. The sweetening and cleaning system 10 and the lapping machines 12 are filled with the lapping compound by deenergizing the three-way valve 52 to allow fluid-flow from the virgin receptacle 14, energizing the first pump 48 on, and energizing the third two-way valve 58 open. The other valves 54, 56, and 60 are closed, and the second pump 50 is deenergized off. The lapping compound is pumped from the virgin receptacle 14, through the first pump 48, through the pipes 116, and added into the machine reservoir 24. The machine reservoir 24 is filled with the lapping compound until the second level sensor 32 triggers; or until the predetermined time has expired; then the first pump 48 is deenergized off and the third two-way valve 58 is deenergized close. Now the sweetening and cleaning system 10 is ready for the sweetening mode.

As mentioned, the sweetening mode can be initiated after a certain event. Once initiated, the waste is first removed out of the machine reservoir 24. The second pump 50 is energized on and the second two-way valve 56 is energized open. The other valves 54, 58, and 60 are closed, and the first pump 48 is deenergized off. The waste is pumped from the machine reservoir 24, through the second pump 50, through the pipes 118, and into the waste receptacle 18. The waste is pumped out of the machine reservoir 24 until the first level sensor 30 triggers or until the predetermined time has expired; then the second pump 50 is deenergized off and the second two-way valve 56 is deenergized close. After the waste is removed, the lapping compound is added to the machine reservoir to improve the compound therein. To do this, the three-way valve 52 is deenergized to allow fluid-flow from the virgin receptacle 14, the first pump 48 is energized on, and the third two-way valve 58 is energized open. The other valves 54, 56, and 60 are closed, and the second pump 50 is deenergized off. The lapping compound is pumped from the virgin receptacle 14, through the first pump 48, through the pipes 116, and added into the machine reservoir 24 until the second level sensor 32 triggers or until the predetermined time has expired. Now, waste has been pumped out of the machine reservoir 24 and replaced by lapping compound thus improving the compound in the lapping machine 12 and thus completing a sweetening event for that machine.

Once the cleaning mode is initiated, the lapping machine 12 is first purged. The waste is removed out of the machine reservoir 24 and into the waste receptacle 18. The second pump 50 is energized on and the second two-way valve 56 is energized open. The other valves 54, 58, and 60 are closed, and the first pump 48 is deenergized off. The waste is pumped out of the machine reservoir 24 until the low level sensor 28 triggers until all of the level sensors 32, 30 and 28 show no fluid; then the waste is continually pumped out of the reservoir for a predetermined amount of time, for example 20 seconds, to scavenge any remaining waste to ensure that the waste is almost entirely emptied out of the reservoir. After the predetermined 20 seconds, the cleaning compound begins being added to the machine reservoir 24. To do this, the three-way valve 52 is energized to allow fluid-flow from the cleaning receptacle 16, the first pump 48 is energized on, and the third two-way valve 58 is energized open.

The cleaning compound continues being added to the machine reservoir 24 after the predetermined 20 seconds for another predetermined amount of time that is sufficient to replace the volume of fluid in the pipes. The reservoir is filled until the second level sensor 32 triggers. If the second level sensor 32 triggers before the predetermined amount of time has expired, then the first pump 48 is deenergized so that cleaning compound is no longer added to the machine reservoir. In any case, cleaning compound can be added to the machine reservoir 24 and the associated pipes, including pipes 116 and 118, so that cleaning compound is substantially the only fluid in the pipes and reservoir.

Now, the cleaning compound is continuously recirculated through a bypass loop and through the lapping machine 12 to clean the associated flow-paths. The bypass loop is created by energizing the three-way valve 52 to allow fluid-flow from the cleaning receptacle 16, energizing the first pump 48 on, energizing the fourth two-way valve 60 open, and energizing the first two-way valve 54 open. The second and third two-way valves 56 and 58 are closed, and the second pump 50 is deenergized off. The cleaning compound is continuously recirculated through the bypass loop to remove build-up and the like therein for a predetermined amount of time. Particularly, the cleaning compound is pumped from the cleaning receptacle 16, through the first pump 48, through the pipes 116, past the fourth two-way valve 60, through the pipes 118, through the first filter 62, and back into the cleaning receptacle 16. Simultaneously, the cleaning compound is continuously recirculated through the lapping machine 12 for the same predetermined amount of time. The machine pump 34 pumps the cleaning compound from the machine reservoir 24, through the second filter 64 (if provided), through the machine cell 22, and back into the machine reservoir 24. After the predetermined time is up, the now-used cleaning compound is routed to the waste receptacle 18, and the sweetening and cleaning system 10 and the cleaned lapping machines 12 are then primed with the lapping compound as described above.

The bypass loop is also used when the machine operator selects a bypass mode on the PLC 20. The bypass mode then diverts fluid-flow away from the particular lapping machine 12, for example, for servicing the lapping machine or in case of a failure. This way the sweetening and cleaning system 10 is not shutdown altogether and the other lapping machines in the group that are not being serviced are sweetened and cleaned.

Those skilled in the art will appreciate that the above description of the sweetening and cleaning system and method can vary with different lapping operations. For example, the above described components may not necessarily be installed in the particular location described or even exist in other systems while still coming within the scope of this invention. And indeed, the sweetening and cleaning modes may be performed in different ways while still coming within the scope of this invention.

It is to be understood that the foregoing description is not a definition of the invention, but is a description of one or more preferred exemplary embodiments of the invention. The invention is not limited to the particular embodiment(s) disclosed herein, but rather is defined solely by the claims below. Furthermore, the statements contained in the foregoing description relate to particular embodiments and are not to be construed as limitations on the scope of the invention or on the definition of terms used in the claims, except where a term or phrase is expressly defined above. Various other embodiments and various changes and modifications to the disclosed embodiment(s) will become apparent to those skilled in the art. All such other embodiments, changes, and modifications are intended to come within the scope of the appended claims.

As used in this specification and claims, the terms “for example,” “for instance,” and “such as,” and the verbs “comprising,” “having,” “including,” and their other verb forms, when used in conjunction with a listing of one or more components or other items, are each to be construed as open-ended, meaning that the listing is not to be considered as excluding other, additional components or items. Other terms are to be construed using their broadest reasonable meaning unless they are used in a context that requires a different interpretation. 

1. A sweetening and cleaning system for one or more lapping machine(s), comprising: a virgin receptacle holding a lapping compound and being piped to the lapping machine(s); a cleaning receptacle holding a cleaning compound and being piped to the lapping machine(s); a waste receptacle holding waste that is piped from the lapping machine(s); and a first pump that pumps the lapping compound from said virgin receptacle to the lapping machine(s) during part of a sweetening mode of the sweetening and cleaning system, and that pumps the cleaning compound from said cleaning receptacle to the lapping machine(s) during part of a cleaning mode of the sweetening and cleaning system.
 2. A sweetening and cleaning system as defined in claim 1, further comprising a second pump that pumps waste from the lapping machine(s) to said waste receptacle during part of both the sweetening and cleaning modes of the sweetening and cleaning system.
 3. A sweetening and cleaning system as defined in claim 2, further comprising: a first level sensor located in a machine reservoir of the lapping machine(s) that is adjustable so that said first level sensor is set to determine the amount of waste that is pumped out of the machine reservoir by said second pump during the sweetening mode; and a second level sensor located in the machine reservoir that is set to determine the amount of lapping compound that is pumped into the machine reservoir by said first pump during the sweetening mode.
 4. A sweetening and cleaning system as defined in claim 2, further comprising: a first skid constructed to carry said virgin receptacle, said cleaning receptacle, said waste receptacle, and said first pump; and a second skid constructed to carry said second pump.
 5. A sweetening and cleaning system as defined in claim 1, wherein said first pump is a single peristaltic pump that is piped to both said virgin receptacle and said cleaning receptacle.
 6. A sweetening and cleaning system as defined in claim 5, further comprising a three-way valve having a first inlet port connected to said virgin receptacle, a second inlet port connected to said cleaning receptacle, and an outlet port connected to said peristaltic pump, said first inlet port being selectively open during part of the sweetening mode, and said second inlet port being selectively open during part of the cleaning mode.
 7. A sweetening and cleaning system as defined in claim 1, further comprising: a first two-way valve having an inlet port connected to the lapping machine(s) and an outlet port connected to said cleaning receptacle, said ports being selectively open during part of the cleaning mode; and a second two-way valve having an inlet port connected to the lapping machine(s) and an outlet port connected to said waste receptacle, said ports being selectively open during part of both the sweetening and cleaning modes.
 8. A sweetening and cleaning system as defined in claim 7, further comprising: a third two-way valve having an inlet port connected to said first pump and an outlet port connected to the lapping machine(s), said ports being selectively open during part of both the sweetening and cleaning modes; and a fourth two-way valve having an inlet port connected to said first pump and an outlet port connected to said cleaning receptacle, said ports being selectively open during part of the cleaning mode.
 9. A sweetening and cleaning system as defined in claim 1, further comprising: a first filter located downstream the lapping machine(s) and upstream said cleaning receptacle that filters cleaning compound during part of the cleaning mode; and a second filter located downstream a machine reservoir of the lapping machine(s) and upstream a machine cell of the lapping machine(s).
 10. A sweetening and cleaning system as defined in claim 1, further comprising a programmable logic controller (PLC) that communicates with the lapping machine(s), reads inputs from various components of the sweetening and cleaning system, sends outputs to control the various components, and employs a human-machine interface (HMI).
 11. A sweetening and cleaning system as defined in claim 1, further comprising a plurality of pipes connecting said virgin receptacle, said cleaning receptacle, said waste receptacle, and the lapping machine(s), wherein said pipes share a generally uniform diameter throughout their length and change directions through about 45° laterals and sweeping radiuses that is a multiple of 6 times said pipe diameters.
 12. A sweetening and cleaning system as defined in claim 1, wherein said virgin receptacle is piped to a three-way valve, said cleaning receptacle is piped to said three-way valve, said three-way valve is piped to said first pump, and said first pump is piped to the lapping machine(s).
 13. A method of sweetening and cleaning one or more lapping machine(s), comprising: providing a virgin receptacle that holds a lapping compound, a cleaning receptacle that holds a cleaning compound, and a waste receptacle that holds waste; in a sweetening mode, removing waste out of a machine reservoir of the lapping machine(s) and pumping the waste directly to said waste receptacle; in the sweetening mode, adding the lapping compound to the machine reservoir; in a cleaning mode, purging the lapping machine(s) by removing waste out of the machine reservoir and pumping the waste to said waste receptacle, and adding the cleaning compound to the machine reservoir; and in the cleaning mode, priming the lapping machine(s) by adding the lapping compound to the machine reservoir.
 14. A method of sweetening and cleaning as defined in claim 13, wherein the purging further comprises recirculating the cleaning compound from said cleaning receptacle to a bypass loop that bypasses the lapping machine(s) and back to said cleaning receptacle for a predetermined amount of time to clean said bypass loop, and concurrently recirculating the cleaning compound through the lapping machine(s).
 15. A method of sweetening and cleaning as defined in claim 13, wherein the purging further comprises emptying the cleaning compound out of the machine reservoir.
 16. A method of sweetening and cleaning as defined in claim 13, further comprising providing a first pump that pumps the lapping compound out of said virgin receptacle and pumps the cleaning compound out of said cleaning receptacle, and a second pump that pumps waste from the machine reservoir to said waste receptacle.
 17. A method of sweetening and cleaning as defined in claim 13, further comprising, in the sweetening mode, removing the waste out of the machine reservoir for a predetermined amount of time and adding the lapping compound to the machine reservoir for a predetermined amount of time.
 18. A method of sweetening and cleaning as defined in claim 13, wherein the purging further comprises removing waste out of the machine reservoir to a set low level in the machine reservoir, and adding the cleaning compound to the machine reservoir to a set second level in the machine reservoir.
 19. A method of sweetening and cleaning as defined in claim 18, wherein the purging further comprises continuing to remove waste out of the machine reservoir after the set low level for a predetermined amount of time.
 20. A method of sweetening and cleaning as defined in claim 13, wherein the sweetening mode is automatically initiated after a predetermined event, and the cleaning mode is automatically initiated after a predetermined event.
 21. A sweetening and cleaning system for one or more lapping machine(s), comprising: a virgin receptacle holding a lapping compound and being piped to the lapping machine(s); a cleaning receptacle holding a cleaning compound and being piped to the lapping machine(s); a waste receptacle holding waste that is piped from the lapping machine(s); a first pump piped to said virgin receptacle, to said cleaning receptacle, and to the lapping machine(s), said first pump pumping the lapping compound from said virgin receptacle to the lapping machine(s) and pumping the cleaning compound from said cleaning receptacle to the lapping machine(s); a second pump piped to said cleaning receptacle, to said waste receptacle, and to the lapping machine(s), said second pump pumping waste from the lapping machine(s) to said waste receptacle; and a three-way valve located downstream said virgin and cleaning receptacles and upstream said first pump, said three-way valve regulating fluid-flow between said virgin receptacle, said cleaning receptacle, and said first pump. 